The dried material is forced through holes in a die and cut to the chosen length.

Subcoal (R) pellets destined for on-site analysis.

An assortment of metallic content removed by the plant’s magnets and eddy current system.

8mm Subcoal (R) ‘fluff.’

16mm Subcoal (R) pellets.

Subcoal pellets can be handled much like any other fuel or input material.

Lars Jennissen, N+P Group

Global Cement recently visited the N+P Subcoal® plant in Farmsum, near Groningen, the Netherlands to find out about the history of the N+P Group, the Subcoal® manufacturing process, the current markets for Subcoal® products and the company’s plans for the future. Peter Edwards spoke with Lars Jennissen, Technical Director at N+P Group...

Introducing the N+P Group

Global Cement (GC): Please could you briefly introduce the N+P Group to our readers?

Lars Jennissen (LJ): The N+P Group is a family-owned company founded by my father Karel Jennissen in 1992. We celebrated 25 years of operation last year. Everything we do is related to recycling and there are two main areas: Waste to raw materials and waste to alternative fuels. On the alternative fuel side we produce a range of products: solid recovered fuel (SRF), refuse derived fuel (RDF), tyre-derived fuel (TDF) and Subcoal®, which we make here at our Farmsum plant. The group handles around 2.5Mt/yr of alternative fuels and alternative raw materials.

The first alternative fuel production plant in the group was established with a joint-venture partner in Germany in 1993. It produced around 2t/hr and supplied a kiln in Antoing, Belgium. In 1996 the family took over 100% control to develop both activities.

In 2003 we set up a joint venture with an alternative fuels plant close to Farmsum that has since closed. With this we exported alternative fuels to the UK for the first time in collaboration with a multinational cement producer. This helped to expand the interest in alternative fuels in that country.

At present we have the Subcoal® plant here at Farmsum and we sell third-party alternative fuels that meet our criteria around Europe. In the UK we blend a range of third-party fuels at a plant in Grimsby, Lincolnshire. We export from there all over Europe. Another activity in the UK is helping alternative fuel producers to improve their production processes to ensure that their output can be used by cement plants.

Introducing the Subcoal®

GC: Can you introduce the Subcoal® product and brand?

LJ: Subcoal® is a technology to upgrade RDF and SRF into Subcoal® pellets, which can be used to replace fossil fuels in cement and lime plants, blast furnaces and power generation facilities. The pellets are similar to bituminous coal in terms of calorific value and they can be treated the same physical way. The pellets are mainly used as a powdered fuel, <5mm in size, after being ground in a conventional mill. They are also very dense compared to SRF and RDF, which presents storage and transit advantages.

GC: How was the Subcoal® process developed?

LJ: The Subcoal® brand and product had a long and difficult birth. The concept was initially developed by Dutch State Mines (DSM) in 1998. DSM was a plastic producer at the time and it had used part of its research and development budget to investigate ways to add value to waste plastics. The project was shelved for 10 years before two staff members at DSM decided to resurrect it in 2008, with a spin-off company called Qlyte.

Qlyte wanted to develop Subcoal® globally as a technology provider but it found that nobody was prepared to invest when it was so new. The decision was taken to build a demonstration Subcoal® plant. It built the Subcoal® plant at Farmsum in 2010.

At this point N+P’s involvement began, first as a supplier of input materials. However, Qlyte couldn’t make the business work and suffered heavy losses, after which the various shareholders approached us. They had lost a lot of money and we had a lot of discussions about whether or not N+P should take over running the plant. For N+P it was not so much of a risk, as the main equipment was all in place and we had confidence in the market for this type of fuel. What we did have to invest was significant time and labour, as well as money. We decided to do it on the basis of N+P holding the majority of shares and injected the necessary funds.

We acquired a majority shareholding from that point so that we could direct the recovery of the plant. The first thing we had to do was overcome the negative connotations of the Qlyte name. We had to convince customers that product being made by us was not the same as before. To do this, we changed the name of the company to Subcoal Production. This worked well. At the end of 2014 we had around 35,000t of pellets in storage. By the start of 2016 we had sold all of this and were sold out on continued production. In 2016 our Subcoal activities turned a profit for the first time and we invested in new capacities.

In October 2017 N+P acquired the remaining 33% of Subcoal International and Subcoal Production that it did not already own to become a 100% shareholder of both. We now want to develop the concept internationally, as the second plant is scheduled to start operation in the UK at the end of 2018.

Making Subcoal® pellets at Farmsum

GC: Where does the ‘raw’ material for Subcoal® come from?

LJ: The plant was initially designed to use 100% paper reject, which is the assorted plastic that comes from the paper recycling sector. The problem is that this material is high in chlorine and moisture, two things that cement producers do not like to put into their kilns. To counteract these problems, we now use a lot of pre-processed RDF and industrial waste streams. We also use other materials that have been pre-processed as part of the paper-making process and higher-quality mixed plastic waste.

Our big advantage is that we don’t ‘own’ any waste, we are ‘waste ambivalent.’ If a supplier is not able to provide the right quality, another will be able to and we might chose to use them instead. There are a lot of things to get right when you are making Subcoal® pellets. You have to know all of the suppliers and what each of them can bring to the table.

In terms of where the material is from, we source from the Belgium, Germany, the Netherlands and the UK. These are countries that have fairly sophisticated waste processing systems, which helps to keep the input consistent.

GC: How are Subcoal® pellets made in Farmsum?

LJ: The exact material in any given ‘recipe’ is affected by the exact pellet product that we are making, which, in turn, depends on the industry that will use the pellets. The materials are mixed using loaders outside of the plant according to the recipe. Material from this general mix is then put into a bunker and goes through a screen, with the fines going directly to the process. A Lindner shredder then takes the coarse material and shreds it to <100mm. At this point we can add RDF, which is quite dry, if we see that the general mix has high moisture levels. We do this because the drying capacity is limited in the plant and the RDF will reduce the total moisture. The coarse material goes to a bunker. The fines and the coarse streams are recombined, before a series of magnets and an eddy current separator remove the ferrous and non-ferrous metals. This is a crucial step due to the way that the pellets are made later in the process.

Then the material goes to a gas-fired dryer, which uses hot air to dry the incoming waste streams. The dried material then goes to a cyclone, two Pellenc optical sorters for PVC and two secondary shredders from Bano to shred the material to the required size for pelletising.

There is then a feeding and buffer system, which feeds the material to the four pelletisers. The diameter of the hole through which the material is forced (i.e. the diameter of the pellets) can be set at 6-16mm. The length of the pellets can be adjusted by altering the distance between the die (hole) and the knife. After the pelletisers, there is a cooling step, because the pelletiser generates quite a lot of heat, although it is purely the mechanical forces that partially melt and press the pellets together. After the cooling step, the pellets are stored in our covered stockyard.

Of course, a process engineer looks at this set up and says, ‘Given that each mechanical step dries out the material, why not move the dryer to the end?’ This is one of many questions that could be, and rightly have been, asked about the plant. This is not the way it would be built if we started from scratch now. However, the plant presents a great test bed to learn the best way to make Subcoal® pellets.

GC: What is the production capacity at present?

LJ: The plant processes about 1750t of input material into pellets per week. Once the water has been evaporated during the process, this leaves 1300t of pellets. Total production is around 68,000t/yr.

GC: What do you do with your rejects?

LJ: The largest part, around 15% of the lost weight, is moisture, which goes up the stack. About 6% of the input mass is solid reject material. The rejects include metals, low CV wood and inert materials like stones. The bulk of the solid waste goes to a waste incineration plant.

GC: What are the properties of Subcoal® pellets?

LJ: First and foremost they are, obviously, solid fuel pellets. Traditionally when people think of alternative fuel pellets, they think of loosely-held together ‘non-lumps’ of material that fall apart as soon as you look at them. Many people would quite rightly ask, ‘Why pelletise?’ and point out that non-processed RDF or SRF is just as good. However, that’s missing the point. Subcoal® pellets replace coal or petcoke, not RDF or SRF.

Subcoal® pellets are very dry in comparison to other alternative fuels, with around 5% moisture. For comparison, high-quality SRF has around 10% moisture. The low moisture is a key reason why Subcoal® pellets retain their shape and density when they come out through the die. They are rigid and do not need to be baled, which saves on the baling and unbaling steps typically seen with loose RDF or SRF.

Another characteristic is that it has few of the large wooden and metallic contaminants that can break handling equipment when you use SRF and RDF. Subcoal® pellets also have low ash content. We always aim for less than 12% ash. They have a CV of around 23GJ/t, which is in the lignite range. The lowest CV we would want to sell under the brand is 20GJ/t.

For chlorine, we tailor the level to suit the specific client’s needs: From 0.8% for cement to 1.0% for lime and 1.5% for a blast furnace. We also have to consider the chlorine level per GJ, rather than chlorine per tonne. The cement kiln sees the energy of the fuel being burned and the chlorine associated with that fuel, rather than a given mass of fuel. It’s an important distinction for us that we sometimes have to point out to prospective customers.

In terms of physical advantages, the Subcoal® pellets are easy to handle on site and do not need to be covered. Due to the fact that they have a typical density of 450kg/m­3 rather than 60-100kg/m3 for a typical SRF, the pellets provide handling advantages for the cement plant. Less storage space is required and more can be transported on a single truck.

Another advantage is that our pellets look more like an engineered fuel than SRF or RDF. This can be of great help when a cement producer wants to introduce alternative fuels in countries where they are not commonly used. It helps to convince governments and the wider public that this is a ‘fuel’ not a ‘waste.’

During 2017, we carried out two trials at an independent cement producer in southern Europe. We have co-ground more than 10% Subcoal® pellets with petcoke at the plant, achieving the same percentage of substitution on the main burner without any investment in just 48hr. We used all the existing equipment and the plant’s existing Loesche coal mill to do this.

On top of all this, Subcoal® pellets offer the opportunity to use alternative fuels in kilns that have difficulty using conventional alternative fuels. On one particular kiln we were able to increase the substitution rate from 30% to 60% almost overnight by replacing coal. In that case very short pellets were used directly on the main burner, substituting the main fossil fuel.

When the pellets are ground by themselves in a hammer mill, a powder is produced that has similar combustion characteristics to a liquid fuel. In the future this will be a major use of pellets. A kiln in northern Europe burns up to 85% milled pellets in the main burner, which is exceptional.

We can also supply on a constant basis at a fixed price, unlike many other alternative fuels. We buffer the producer against the fluctuations in the market.

GC: Subcoal® pellets are clearly more expensive for a cement producer. Can you put a number on the difference?

LJ: There are two main costs incurred in Subcoal® pellet production that are not part of SRF or RDF production. First is the dryer cost, which is by far the biggest cost. It is, however, essential to the process. The second cost is the pelletising process, but this is only slightly more overall than the cost of baling SRF or RDF.

In terms of putting a number on it, it’s not possible to talk in general terms due to the different distances and quantities used by individual customers. However, I will say that using Subcoal® pellets is more expensive than SRF/RDF but less expensive than coal. We do know that when importing alternative fuels, our handling advantage makes us quite competitive, surely given the high quality standard of our fuel. This is a pretty strong position to present to prospective clients given the long list of advantages I mentioned above.

Markets and the future

GC: Where does the plant send Subcoal® pellets to?

LJ: So far we have supplied four different sectors in a total of 15 countries with Subcoal® pellets. The biggest proportion is used in three countries: Belgium, Sweden and Germany. Portugal is also quite a major user. None has been used in the Netherlands because the country’s only cement plant will halt clinker production by 2020. It already has alternative fuel supplies in place in any case.

So far Subcoal® pellets have been supplied only within the EU, but we are in discussions with potential customers on every continent. 2018 should be a big year for expansion into new markets. This includes places one might not expect, like the Middle East, because the fuel picture is changing rapidly there. Soon the days of free gas will be gone and the most prepared cement producers are already making preparations for the future. North Africa is another area that is very interested in developing its alternative fuels use and Subcoal® pellets can be an important part of that. Asia is another case where we have a lot of enquiries. However, the governments do not allow imports of alternative fuels at present. We are taking enquiries from all over and that’s great for us. It is commercially viable to send material to South Asia, the Far East, South America and West Africa from this plant.

Driving our expansion will be imports of alternative fuels, which are increasing in many markets. Lots of countries are seeing that their local alternative fuels markets are not developed and will not develop for perhaps five years or more. The traditional way to import is to get in bales, but that requires a lot of up-front costs for debaling machines, feeding systems and so on. The advantage of putting Subcoal® pellets into the plant’s existing coal mill are enormous. 10% substitution can be achieved overnight in the most unlikely plants, simply by adding the pellets to the coal mill and using existing equipment.

GC: In that case, how do you think Subcoal® will affect demand for ‘traditional’ alternative fuel handling equipment?

LJ: My previous answer might appear to suggest that there could be a significant drop in demand for specialist handling equipment at cement plants. This may be the case for individual plants but the equipment will still be needed at Subcoal® pellet plants. At the same time, we (and others) still supply SRF and RDF to main burners, which will continue to require the kind of equipment that the sector is familiar with.

GC: Which transport methods are used to serve customers?

LJ: Around 75% is supplied loose in vessels and 25% is by road. Within the road distribution portion we have a split between containerised pellets and loose pellets on walking floors. We are also piloting the use of rail for a specific blast furnace client.

GC: What are the future plans for the Farmsum plant and others like it?

LJ: Going forward, we want to take the plant to 1800t/week, around 94,000t/yr, as a minimum target. This will be via a number of incremental changes and process improvements. It’s an ongoing process. This will make the plant as flexible as possible to accommodate future changes in the incoming material, the alternative fuels sector and the waste-to-energy sector. As part of our aim to have the lowest possible CO2 footprint, we plan to set up a small waste-to-energy plant to supply our dryer with heat from alternative fuels. That would require the types of waste that the Subcoal® process is unable to use.

Away from this plant, we are also building a plant in Teesport, North Yorkshire, UK, which will use around 200,000t/yr input materials. It is more than double the size of the Farmsum plant. In this new facility, we are using our experience from Farmsum to build one of the most sophisticated facilities for alternative fuel production anywhere in the world. It should be ready by the fourth quarter of 2018 and the output is already contracted.

There is also a plan to build a 11,000t/yr Subcoal® plant at a paper recycling plant in the Netherlands. We also plan a third major Subcoal® pellet plant in Austria or Italy to cover South Eastern European locations like Serbia, Bulgaria, Albania and other countries that we have had enquiries from. In the five year timeframe, it would be great to be making Subcoal® pellets outside of Europe.

Morocco has imported material in the past but now it is banned once more because the material imported was very poor. Alternative fuels did not make a good first impression there. Senegal is importing waste and we are having good discussions in Argentina and Brazil. We also have discussions ongoing in the Far East, for example in Thailand, as well as in the range of Middle Eastern locations I mentioned earlier.

GC: How do you plan to develop the product?

LJ: We will continue to expand the range according to the needs of our clients and future clients. We have already expanded the range of pellets to include what we (somewhat confusingly) call Subcoal® ‘fluff.’ This is a partly flaked 8mm wide pellet that can be fed directly to the main burner.

GC: Isn’t that turning the pellet back to ‘not a pellet’ anymore?

LJ: It seems like a lot of processing but to turn light and fluffy RDF or SRF into dense, hard, easy-to-handle, high CV fuel upgrades the material enormously. See my previous example of increasing substitution up to 75% within a few weeks.

LJ: We are keen to expand into other markets, not just cement. I already mentioned lime, the power sector and blast furnaces. If these industries decide to use Subcoal® pellets in a big way, the ramifications could be significant. For example, we have had discussions with a power plant in Europe to supply it with Subcoal® pellets. If the plant converted just two of its 110MW units to use the pellets, it would need 1Mt/yr of pellets. It is clear that the potential for this type of product is huge, both inside and outside of the cement sector. I am unable to say exactly how it will change, but we will always respond to the needs of the market.

GC: What is the biggest hurdle to expanding the production and hence use of Subcoal® pellets?

LJ: I think for the cement sector it is not a case of ‘if’ but ‘when’ the countries I mentioned above, and others, start to take Subcoal® pellets. The biggest thing that we can do to help this along, aside from producing the pellets, is to work with the government of the Netherlands to achieve ‘end of waste’ status for the material. Progress is going well at this point. If we achieve product status here, the likelihood is that this will be accepted in many other countries, greatly facilitating exports and acceptance. This is due to the fact that the more stringent rules apply in such cases.

GC: Can you put a figure on how much Subcoal® that could be sold going forward?

LJ: With our current customer list, we could potentially contract around 0.5Mt/yr of Subcoal® pellets. However, as the power plant example I provided illustrates, the potential really is unlimited!

GC: Lars, thank you for your time today.

LJ: You are most welcome indeed!

Profile: Lars Jennissen

Lars Jennissen joined the family business in 2007, along with his younger brother Stijn. He began in the logistics department and moved through all the different departments to get a grounding in the business. Over the period that he has worked for the company there has been significant expansion. When he joined N+P had just 15 employees and now it has 80.

Today Lars is responsible within the N+P Group as Technical Director and managing director of the Subcoal companies within N+P. He is also responsible for developing the market for Subcoal® and N+P’s other products.